Koalas at Cape Otway
Koalas in the Otways:
understanding the facts
Victoria and South Australia have large and
thriving koala populations, especially around the
coastal areas of Cape Otway which contain one of
the most favoured koala habitats, Manna Gum
woodland.
In contrast to Victoria and South Australia’s secure
koala populations, koala populations in Queensland,
New South Wales and the Australia Capital Territory
are in decline and have been listed as Vulnerable under
the Environment Protection and Biodiversity
Conservation Act 1999.
Cape Otway koala population
Due to hunting, land clearance, wildfires and disease
pressure, koala populations declined significantly in the
late 1800s, leaving only a few remnant populations on
the mainland and some translocated populations on
French and Phillip Island.
From the 1920s to 1980s, translocation programs
successfully reintroduced koalas back to what is
thought to be their natural range in Victoria.
In the 1980s, 75 koalas were successfully reintroduced
to Cape Otway from French Island. These animals are
the founding individuals of the current Cape Otway
koala population.
The favourable climatic conditions at Cape Otway,
along with the absence of predators, disease and
wildfires, and a high koala fertility rate, has enabled
the Cape Otway koala population to grow rapidly.
The population inhabits the favoured Manna Gum
woodland, which occurs predominantly on private
farmland.
Koala over-abundance
At the time of the translocation to Cape Otway the
Manna Gum woodlands covered approximately 450
hectares. No significant land clearing has occurred
since the introduction, but over-browsing by the
rapidly increasing koala population has significantly
reduced the condition and amount of habitat.
A sustainable koala density in Victoria is considered to
be less than one koala per hectare in most native
forests and woodlands.
By 2013 and 2014, koala population densities were
reaching up to 20 koalas per hectare at Cape Otway.
Current koala densities at Cape Otway vary, but are as
high as 17 per hectare in some areas.
Once koala numbers increase beyond the carrying
capacity of the habitat, koalas eat all of the accessible
gum leaves, including any re-growth, ultimately killing
the trees. Without a sufficient food source to sustain
them, the health of the koala population quickly
declines, resulting in koalas starving and eventually
dying.
Koalas are able to move from the favoured Manna
Gum woodland on private land into the adjacent mixed
species forests of the Great Otway National Park, but a
rapid change in diet is not easily tolerated and koalas
are reluctant to move from the Manna Gum trees.
Managing koala over-abundance
In Victoria, koala over-abundance is a long term and
complex issue that is challenging to manage. Koala
welfare and habitat health are the key drivers of any
actions taken to manage over-abundant koala
populations.
Management of over-abundant koala populations can
involve a range of measures aimed at improving the
welfare of the koalas and the health of the vegetation,
including translocation, fertility control and tree
protection. In extreme cases welfare interventions may
need to take place to ease the suffering of any sick or
starving koalas.
Koalas at Cape Otway
Successful translocation of koalas relies on a number of
factors, including the health of the koala, identification
and selection of suitable habitat that has food trees
similar to those the koalas are being removed from,
recipient habitat that does not already support a
significant existing koala population, and the koalas
own ability to deal with the stress of translocation and
adapt to a changed diet.
Previous actions
When the Cape Otway koala population density
reached an unsustainable peak in 2013, an emergency
welfare intervention program was initiated by the
Department.
The health assessments involved the capture, sedation
and examination of individual koalas with a focus on
body condition. Unhealthy koalas, which were deemed
too sick to survive in the wild were humanely
euthanased to prevent further suffering.
Preliminary results from the assessment of a
representative sample of 100 koalas, has confirmed
that further action will need to be taken to manage the
welfare of the koalas. For a copy of the Management
Actions see www.delwp.vic.gov.au.
Did you know?
During the interventions, captured koalas were
assessed by veterinarians based on Koala Welfare
Assessment Guidelines, developed by Zoos Victoria
veterinarians and the Department.
A total of 960 koalas were assessed with 686 koalas
found to be in very poor health (diseased or
emaciated) and were subsequently humanely
euthanased by veterinarians. The euthanasia of koalas
was not undertaken lightly, but was considered
necessary to protect koala welfare.
Koala density is still high at Cape Otway and proactive
management of the population and koala welfare is
needed.
Current actions
In early 2015, DELWP consulted with animal welfare
and ecological experts on how to proactively manage
the koala overabundance at Cape Otway.

Koalas are long lived and females usually
produce one offspring each year, meaning
populations have the potential to increase
rapidly.

Koalas at Cape Otway lack natural predators,
are relatively disease free, and as a result
populations have the ability to double in size
every three years.

The koala’s diet consists solely of Eucalyptus
leaves which are low in energy. As such, koalas
require a large volume of food and spend
many hours a day feeding.

The Cape Otway Manna Gum woodlands are
part of a vulnerable Ecological Vegetation Class
known as the Damp Sand Herb-rich Woodland.
Currently less than 10-30% of its natural extent
remains in the area.
DELWP now has management actions in place, which
aim to achieve healthy native forests and a sustainable
population of healthy koalas at Cape Otway.
The first recommended action by the expert panel was
a koala health assessment, completed in May 2015.
The purpose of the assessment was to gain information
about the current health status of the population and
how that relates to the current condition of habitat.
The koala health assessment was undertaken by small
teams, including experienced koala catchers,
veterinarians and staff from the Department of
Environment, Land, Water and Planning.
A koala being released at Cape Otway after a health
assessment.
© The State of Victoria Department of Environment, Land, Water and Planning 2015